There have been proposed methods wherein data dubbing is made at relatively low speeds between a recording system and a reproduction system both of which use recording media for recording compressed data (for example, see Japanese Laid-Open Patent Publications No. 332960/1992 (Tokukaihei 4-332960) and No. 258834/1992 (Tokukaihei 4-258834)). In accordance with these methods, a recording medium whereon compressed data is recorded is reproduced by a system on the reproduction side, and the reproduced data is recorded on another recording medium by another system on the recording side. However, these dubbing methods do not suggest anything about how to make a dubbing at high speeds.
In order to dub data at high speeds, there has been known a method wherein data is temporarily stored in a buffer memory by using a reproduction bit rate on the reproduction side that is N (natural number) times as great as a normal bit rate, and the stored data is read on demand and written in a recording medium on the recording side.
With this method, it is possible to make data dubbing virtually N times as fast as the normal speed. The following description will discuss the conventional high-speed dubbing method by exemplifying a case wherein a compact disk (hereinafter, referred to as CD) reproduction apparatus is used on the reproduction side and a mini disk (hereinafter, referred to as MD) recording apparatus is used on the recording side.
The MD recording apparatus compresses inputted digital data into almost one-fifth the size of the data amount. For this reason, suppose that the recording bit rate of the MD recording apparatus is equal to the reproduction bit rate of the CD, it is possible to increase the reproduction bit rate of the CD by almost five times. In other words, data reproduced in the CD reproduction apparatus by using a reproduction bit rate that is almost five times as great as the normal bit rate is stored in a buffer memory, and after accessing and track jumping with respect to a desired recordable area in the MD, the data is read from the buffer memory on demand, and written in the MD. Thus, data dubbing is made from the CD on the reproduction side to the MD on the recording side at high speeds.
However, in the above-mentioned conventional high-speed data dubbing method, the reproduction bit rate on the reproduction side is N (natural number) times as great as the normal bit rate. For this reason, writing operations and interruptions between them take place very frequently, and space areas in the buffer memory are virtually reduced by one-Nth. Moreover, this results in an increase in the number of the accessing processes and track-jumping processes to desired recordable areas, and during these operations, data is being stored in the buffer memory at the above-mentioned reproduction bit rate. As a result, the space areas in the buffer memory are further reduced. In addition, in the event of an erroneous accessing process or track-jumping process to a desired recordable area, the space areas in the buffer memory are further reduced.
In other words, the greater the reproduction bit rate, the more frequently the accessing processes and truck-jumping processes to desired recordable areas take place. This results in a higher probability of overflow in the buffer memory, thereby raising a serious reliability problem in data dubbing.